Method of manufacturing rolls.



rr' ya ,OLIVER B. v MGMILLIN,

onPIfrTsBUReH, Y.meanest?rivelare., Assrerlton.` rro PITTSBURGH 1to1-.Ls Vcom?oyanr'rrom 'A ,ooRIoRATIoN or VIRGINIA.

METHOD' oze- MsNUFeeTUeINe Rotes;

' Specification. of Letters Patent.

Patented Mar. 4, 1,919,

YNo Drawing# l Apnlieetion filed Marehv, 191,8.. Seidel No. 220,810,

To aZZ'wwmtmqg/concem: f *f Be it known that'I',- OLIVER Bj, MGMILLIN, a'citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have irrvfented"ceri tain new and useful ImprovementsinlVl'ethfV ods vof Manufacturing Rolls, ofrwhich .the following a specication. f

My invention consists of anv improvement in the manufacture of rolls for rolling mills, and is particularly applicable to the making of chilled rolls. L?" l Heretofore, such rolls lhave ordinarilybeen made from metal melted in ya cupola orair furnace, in either type of'l which the control of 'the velements forming theV melt is more A,or less, uncertain, and especially asto the sul; fur and carbon content,g because of the fuel employed: and the inab'iflitywto control' the supplyof fuel and its consistency. In the making'of chilled rolls, it isdesirable that the carbon content of the rolly at its Wearing face, and for a considerable depth inwardly therefrom, vshall be in combined form. Also that the range of carbonshall 'bevv within 2.76% tor 2.95% for best results(Y ln rol-ls of large section the carbonY should be com bined'form at least l{go-extensive with the depth ofthe chill, and preferably somewhat beyond such depth'toward thel center. j vAlso that the change" from ,combined carbon to graphitic carbon shall 'not be abrupt, rbut gradual, and merging the one into the other.

i In chilled rolls it,` isfalsogvery desirable to A. graphitic form. Ii'kewise, in'

have all other portions except Vthe working ieee of the rollwhere strengthisiequired; of a composition in which the kcarbon is the` 'making oie-,chilled rohe, their intended use as finishing Irolls and dur-y ing thelest passes off plates, rails, ete,

wherein the smallest percentage of reduction iS aCCOHlplished in the latter'pagses of 13h@ metalv through the rolls7 it is desimblein a? m11- Of' the usual Ql Ordinary 'grey iron mixture,to pretty accurately control the proporf tive-and affected by the dualityv and kind of thev ,fuel employed, its volume, the relative 4. proportion of air, vand` the constant maintee nance of the ideal'proportions. The carbon content also, is especially @'ieqtedby them in: fillettes.` i e Y .Because ofthelqtehty and eine @fthe feel used and the vuhoeettiiity as. to.` itseontrol and. active e'eot on. the` Contents of the cupola orordinaiy sir fornace, the results in themixtdre inf suoli. forms of inmates, as

ordinarily heretoiore. used in the. making 0f l oomnieroial Chilled'y rolls, hare 'been dhd.

heoessahily aremoreor less uncertain results inaeonslderahle variation in the:

chemical eonsistehey and eoiitentof the. cast-l ing, inv oohtrast with the. desired analysis and in marked variation from theagialysis of the heteh. es.. originally made 11n-. The

rolls ih Whiloh; thefdenth of chill is either too r deep. onto@l shallow.. diie. to undesirable variation in some of the. essentiel Aalternent.s This. is' especially truejpas to salitre and carbon.k Y

Thus, en; vorigilial c.

ing' casting having the' same corresponding 'oh,ethical'echtent;` vary Widely there: from, esillustrated irl 'the followingfori 'lhe hateh. as made-'11m for instante for geod-ihtehdedyresdlts. ih grey-iron chilled casting would eohsist of mixture heyihg' the following typieel' analysis?. -f

Siliojonf dll%, sulfur 1061.961.; phosphorus e i, .ifxtulhe-y or Charge of. Y metal Iliade l1P iyiththe purpose, oli produ@ Vso .4.2% manganese ;,,toaleatmaeea-5 Withftheibalahoeoilthe 1,00% iron",A

.Y Iii changing' this.v ioifhdtllal es in @ethos oi sultan 'or' othehsehsitiye elements l have onen hearth ferne/ee. so as to, maintain 'the proportions very closely `to the desired analysis tel 'athen 270%, to. 32.20%.,

jhs. to thephosphorus, it. is possible to maintain this. element in Y' a v.cupole or 'als u'rrisoe et vdholltthe same desirable neroehtage as originally intended.

However, lthe .sulfur is largely ihereased found thatv YI can control the resulty in` an duel to the presence of freesulfur in the coke i i' iii the cupola'furnacefor in the coalused'in the air furnace. Y.

In either a cupola or air furnace the controlor regulations of theisupplyis Valways more or less uncertain.`

numerous tests,l in connection with special and careful manipulation, I have found that* with a regenerative 'openhearth .furnace off the Siemens type, or similar construction, I ani able to so control the volume and proportions of the fuel, preferably natural gas, as toy accurately control the heat, time. of

melt, oxidation, and the various otherneces sary elements having a' direct efectf'oii the product as produced in the resulting casting,

especially when castin a chillfmold, so that i .the resulting analysis is substantiallyfor ex-v act'ly the saine in the resulting lroll' as that V.desired vand as indicated; for instance, in theV first abovenoted preferred analysis." Thisy is especially trueas tothe sulfur and carbon content,`andthe carbon, as stated, will take the` combined forni throughout the I depth `of the'chill or at the working portions of the resulting roll. Y.

While'I am, ,of course, aware that Vopen hearth furnaces of 'the regenerative type have been used for the,` makingof various castings, and that .the advantages rin some of the respects noted,y are well known, I bev lieve that I am the first to have utilized an open. hearth furnace in .the Vparticular and somewhat technical and special art' of manu-V facturingV chilled rolls, vhaving the chemical Velements combined in substantially 'the .de-

' n sired proportionsindicated.'` l, v,The results in practice have shown definite advantages, increased Vstrength and lwearing qualities, and greater endurance in high carbon gray iron` chilled rolls over anything heretofore produced in this classof rolls. Y

:The practice 'is in marked contrast to that heretofore Vcommonly followed,I utilized and adher'ed'to; by vmakers of this kind yof rolls, andthel results inuse', because of maintain- Ving the integrity ofY the original analysis,

have shown a marked de reeof superiority over y.similar rolls hereto ore manufactured and used.v Y 1 What I'claim and desire to secureby Let-` v ters V'Patent' is p 1. The method of making chilledv rolls, consisting' in forming a mixture of iron containing'silicon, sulfur, phosphorus, Y manganese, Vand lcarbon in predeteri`nined proportions, the manganese being low.; melting the mixture vin an open hearthv furnace while maintaining controland avoiding undesirable variations in proportions of said elementsgand casting the molten-*metal while in such controlled condition in a chill mold,

i substantiallyv as set'forth. i

2. The Ymethod of making'chilled rolls,

Vconsisting in forming a mixture of iron Vcontaining silicon, sulfur, phosphorus, manganese, and carbon in predetermined propor-Y ...maintaining control l and avoiding undesir- After considerable experimentation and; able variations in proportions of the sulfur andffcarbon,and-casting the molten metal while in such controlled condition in achill .mold, substantially as set forth. .f

3.l .The method, yof making chilled rolls, consisting iii forming a mixture of iron'con'- taining silicon, sulfur, phosphorus,` manga- Anese, and carbonin predeterminedproportions, the manganese being low; melting the mixture `in an r`open hearthffurnace while ,maintaining control and 'avoiding undesir-V K able: variations'in proportions of the lsulfur which the carbon contentat its facerandfor a limited distance inwardly 'thereof is in combined form, substantially Vas set forth.

4., The methodv of fmakingvr Vchilled rolls,

consisting in forming armixture of iron containing silicon, sulfur, phosphorus, manganese and :carbon in. .predetermined proportions, the manganese being. lowilmelting the mixture in.v an `open .hearth `furnace while maintaining .control f and avoiding undesirable variations in proportions of the 'sulfur and carbon;.and casting the molten metal while in such controlled condition'ina chill mold, wherebyl to forni Aa chilled roll in which the carbon content is in combined form co-extensivewith the depth of the chill, substantially as set forth. Y

5. The inethod of making chilled rolls, kconsisting in forming a mixture.v of. iron containing silicon, sulfur, phosphorus, manganese and carbon in predetermined proper- Y. tions; melting the mixturein an open hearth i furnace while maintaining controll and avoiding undesirableV variations in proportions ofthe sulfur and carbon; and kcasting the molten metal while` in such controlledv conditionin a 'chill mold, whereby to form a chilled roll in which the carbon content :is in combined 4 form co-extensive with the depth of the'chill,and is in graphitic form throughout the central body roll, substantially as set forth.

` 6. A chilled roll formed of a lmixtii'reof iron having.. predetermined and controlled proportions. of` silicon, sulfur, ,phojsphorus,

portion ofthe manganese andY carbon with the carbon ofv e. the outer chilled face portion of theroll in combined form.

7; A Chiiiai mii formed .O f., @mixture 5f' iron? having predetermined and controlled proportionsl of silicon, sulfur, phosphorus,

manganese and carbonV with thev carboni of the 'outer chilled` face portion ofthe rollin combined form and the carbon vof thev inner l body portion yof the rollin graphitic form.V Y

'iso

8. A chilled roll formed of a mixture of iron having contained proportioned elements as follows: silicon .60%, sulfur 061%, phosphorus .42%, manganese .26%, total carbon 2.94% and with'the carbon of the outer chilled face portion of the roll in combined form. Y

9. A chilled roll formed of a mixture of Y iron having contained proportioned elements Copies of this patent may be obtained for chilledk face portion of the roll in combined form and of the inner body Vportion in graphitic form.

In vtestimony whereof I hereunto aiix my signature. Y

` OLIVER BVMCMILLIN.

ve cents each, by addressing the Commissioner of ZEatents,Y Washington, D. C. 

